While vaccinations still appear to reduce a person’s overall risk of catching the delta variant, research published Friday by Public Health England (PHE) found early evidence that people fully vaccinated against Covid-19 may be able to transmit the hyper infectious strain just as easily as those who aren’t.
With their findings outlined in a new technical briefing, PHE scientists said initial analysis of available data indicates that the levels of virus in people infected with the delta variant after being vaccinated “may be similar” to the levels found in unvaccinated people.
PHE called the research just “early exploratory analysis” and wrote that “further targeted studies” are needed to determine the extent to which vaccinated people can spread the delta variant to others.
Separately, the public health agency said another variant on the rise in the U.K., a strain known as B.1.621 that was discovered in Colombia, has shown signs of evading the immune response triggered by Covid-19 vaccines or previous infection.
PHE said “there is preliminary laboratory evidence” suggesting that “vaccination and previous infection may be less effective at preventing infection” with this strain, though there is “no evidence” it is more transmissible than the delta variant, which now accounts for roughly 99% of the U.K.’s new cases.
There have been 37 confirmed cases of B.1.621 in England across six different regions, according to PHE, and it has also been identified in several other countries, including the United States.
The data shared by PHE also showed that of the confirmed delta cases that ended up hospitalized since July 19, 55.1% of the 1,467 were unvaccinated, while 34.9% had received both doses of the vaccine. Experts have highlighted that hospitalizations of vaccinated people does not mean vaccines aren’t working.
“While vaccines provide high levels of protection, they are not 100% and will not stop everyone catching Covid-19,” PHE said on Friday. “As more of the population gets vaccinated, we will see a higher relative percentage of vaccinated people in hospital.”
The findings from Public Health England line up with research released last week by the Centers for Disease Control and Prevention (CDC). As it sought to explain its sudden pivot on mask guidance for vaccinated people, the agency published a study suggesting fully immunized people who contract Covid-19 can spread the virus to others just as readily as unvaccinated people.
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